This application concerns the completion of analysis and reporting of a longitudinal investigation of psychiatric epidemiology, the Stirling County Study. Drawing on a combination of multiple cross-sectional surveys and several cohort follow-up investigations, the main objective is to contribute information about trends, incidence, and outcome regarding treated and untreated psychiatric disorders in a general population. The main bodies of data consist in: 1) self report of symptoms, impairment, and duration of depression and anxiety disorders through structured questionnaire interviews; and 2) reports by general physicians about the full range of psychiatric disorders. Such information was gathered between 1952 and 1970 about 2848 adult residents of a rapidly changing rural environment in eastern Canada. For the longitudinal study, computer programs were designed that substitute for earlier "clinical evaluation" procedures. The first substantive results indicate that the prevalence of depression and anxiety disorders based on self report was 12.5% in a sample surveyed in 1952 and 12.7% in another sample surveyed in 1970. The stability of these prevalence rates is noteworthy. The specific aims involved in completing the study concern: 1) validity of the new computer methods based on using the results of five annual examinations carried out face-to-face by clinical psychiatrists for a subsample of 122 adults; 2) time trend estimates of prevalence based on general physician data; 3) incidence of different types of disorders based on cohort analysis; 4) psychiatric disorder outcomes such as recovery, relapses, chronicity, disability, and mortality; 5) relationships between treated and untreated disorders drawing not only on evidence of care provided by primary physicians but also by psychiatric specialty services as indicated in a case register of a local mental health center; 6) relationships among selected risk factors (organic medical disorders, economic position, social experiences, etc.) and the incidence, duration, and outcome of different types of psychiatric disorders; and 7) evaluation of an explorative trial in prevention.